Process of producing alloys containing yttrium metals of the rare earths



Patented July 16, 1935 UNITED STATES PROCESS or PRODUCING: ALLOYS ooN-TAINING YTTRIUM METALS or THE RARE EARTHS James B. Grenagle, Baltimore,Md; assignor of one-half to William W. Varney, Baltimore, Md., andone-half to Universal Alloys, Incorporated, Baltimore, Md., acorporation of Maryland No Drawing. Application September 18, 1929,

Serial No. 393,582

5 Claims. (01. 75-45) 3 My invention relates to improvements in-themanufacture of steels and alloys, and while or" general application tosteel manufacture, it", plies more particularly to the 'manufacture' o f5 so-called alloy, or self-hardening steels, in which there isincorporated with the steel one or more metals of the yttrium group ofthe rare earths to produce steels or alloys suitable for tools and.other articles requiring metals having special hardness, toughness,tensile strength, etc. The object ofmy invention is to produce steels oralloys having better physical characteristics and also render suchsteels or alloys more uniformand free from defects. i v V r According tomy invention, I incorporate with the metal (scrap) a certain percentage01 the oxalates of the yttrium group of the rare earths alone or incombination with other metals when operating by the crucible method,depending upon the nature of the steel or alloy desired, Theincorporation of the oxalates of the yttrium group of the rare earthsimproves the resulting steel or alloy in any case, and my invention inits broadest aspect comprehends the alloying of the yttrium group of therare earths in the manufacture of steel or alloys in general. 7 g I As aconcrete example which gives satisfaction, an hydroxide of the earths isdissolved in an excess of oxalic acid and nearly neutralized withammonia; crystals form from the solution, and these crystals are washed,dried, powdered, etc., which gives me the oxalates I used. According tomy invention, I form a molten bath of low phosphorous pig iron of anapproximate analysis, which I have found satisfactory, of carbon 2.50%,silicon 1 to 2%, manganese 1%, phosphorus .10%, and sulphur-05%. To thisis added from 50 to 75% of steel scrap and brought to a thoroughlymolten condition. To this bath 40 'is added metallic concentrates ofyttrium, or of the yttrium metals, alone or in combination with othermetals, among which I might mention nickel, chromium, etc., dependingupon the nature .of the steel or alloy desired. The incorporation of themetallic concentrates of the yttrium-metals or the rare earths improvesthe resulting steel its broadest aspect comprehends the alloying of the:yttrium'metals of the rare earths in the manu- 5 facture of steel oralloys in general.

'i My invention relates more particularly to the so -called alloy steelsor self-hardening steels, where the production of a superior high speed:metal suitable for tools for lathes, shapers, drills,

.dies, etc., can be operated at a temperature of molybdenum or tungsten.

and tungsten, especially the former, are more nitrogen or oxygen whichmay be present, thus purifying the metal bath and rendering the re- 2000F.; ior example, when used as a lathe tool it would stand a speeding upofthe lathe to a heating point of the tool to 2000 R, retaining itscutting edge at that temperature.

The toughening and hardening properties given 7 5 to the steel by theyttrium metals of the rare earths, are increased as compared with thosegiven by vanadium, tungsten, chromium, molybdenum, cobalt, etc.,supposedly on account of the lower specific gravity of the yttriummetals of 10 the rareearths, as compared, for instance, with A givenweight of the. yttrium metals of the rare earths having a greatervolume, will exert a greater influence. The oxides of molybdenumvolatile than those of the yttrium metal ofv the rare earths. Inconsequence of this, the effect of the yttrium metals of therare earthsis more permanent when the metal is heated.

Another advantage possessed by the yttrium metals of the rare earths isits resistance to. the action of gases, such as, hydrogen. The yttriummetals of the rare earths also combine with any sultant metal moreuniform.

The yttrium metals of the rare earths as metallic concentrates ormetalloids, singly or in tory oxide, or hydrate, insuring a clean,carboniree metal. For example, Zr (OI-I2) mixed with molasses water andformed under pressure in the mould, dried and calcined at a temperature.of

2000 F., gives satisfactory results. oralloy in any case, and myinvention" in its Another method is to reduce by nieans of carbon, using4 or 5% of charcoal as a reducing agent, the yttrium metals of the rareearths directly from the ores, fergusonite, samarskite, 'gadolinite,euxenite, etc. V 1

I have discovered that the yttrium metals of the rare earths areparticularly adapted torender the iron or steel alloysnon-magnetic,presumably owing to the supposed fact that the iron in its molybdenum,chromium, etc., keeping the resultearths in alloy form. 7

gaseous form is selectively occluded by certain of its elements in theyttrium metals of the rare earths group. I have discovered that as highas of iron may be incorporated and the alloy will still be substantiallynon-magnetic.

I have also discovered that the non-magnetic quality of the alloys bearsa distinct relation to its non-corrosive qualities, and this propertytungsten entirely with the yttrium metal: of the rare earths, a lesspercentage of these, singly or in combination, may be used than thepercentage of tungsten. In case all of the, tungsten is not eliminatedand it is desired to retain a certain percentage of the tungsten whilehaving present theyttrium metals of the rare earths in less quan titythan when'they are used without the tungetch, the proper percentages maybe determined readily by calculation. For example, ab 0ut3 to 6% of theyttrium metal of the rare earths may be used with a 6 to 10% of thetungsten.

' The desired members of the yttrium metal of the r'are earths may beintroduced into the steel or alloy by introducing the concentrates and asuitable reducing agent, such as charcoal, or other suitable reducingagent. 7

Another method is to introduce them in the form of oxides, or' the ferroalloy, just as is done my U. S. Letters Patent No. 1248,6 18, or myLetters Patent No. 1,385,072; 'Still another method which may be usedwhen it is desirable to incorporate other metals, such as hereinbefore'referredto, is to combine the concentrates of the yttrium metals of therare earths with the concentrates of these other metals and then throwthe whole mixture into the steel bath; for example, the concentratestungsten,

ing metal in a freely fluid condition sonims.

In the manufacture of ferrotungsten and termchrome, or other ferroadditive alloys of this nature, the yttrium metal of the rare earthsconcentrated may be mixed with the concentrates of until free oftungsten, molybdenum, chromium, etc., and incorporated with the iron toproduce a ferrotungsten, ferrochrome, ferromolybdenum containing acertain percentage of the yttrium metal of the rare earths. This productcan be distributed as a substitute for the present ferro alloys whichare added to the bath in the production of these steels.

It will be understood that these are merely illustrations and that myinvention is not limited toany particular proportions of the metals, butcomprises in its scope the use of the yttrium metals of the rare earthsalone in steel, or combined with other'alloying metals. In thisspecification and claims, I describe my process and product to cover theyttrium metals of the rare In'this specification and claims, when I usethe term, yttrium metals of the rare earths, I mean, broadly, theyttrium metals of the rare earths group, one sample of which gives thefol lowing analysis; but'Ido not limit myself to the same,'as allsamples differin analysisz Yttrium,

50%, dysprosium, 8%, holmium, 4%, erbium, 6%, thulium, 1%, ytterbium,12%, lutecium 1%, terbium 8%, and contains probably unknown elements,and which I discovered as valuable to the alloys when introduced bymeans of the addition of the group as a'whole, 1 a

The yttrium group taken as a wholeforms an excellent deoxidizer forsteel or cast iron. The

until fusion takes place, and finally reduce current to 40 to 45 v. 600amperes.

The concentrates I have used as set forth hereinI obtained as followstheprocess being the subject matter ofv a pending U. S. patent appuearionseai No 387,268, issued into lEatent No. 1,887,264, on November 8,l932-the'ores used being the yttrium group of the rare earths group 1 Ibreak this into sizes suitable for my operating apparatus, preferablycrushed and ground, but large size may be used. The apparatus used is asimple iron tank into which the ore isthrown mixed with sodiumbisulphate, in the proportion of 1 lb. or the ore and 4 lbs. of sodiumbisulphate. Two electrodes composed of sash-weight metal, a very. hardiron of poor quality, 'containingperhaps silica and other impurities,are introduced into the mass content of the tank near the opposite sidesthereoff Electric terminals are at tached tothese electrodes and adirect current is permitted to flow between the terminals; in

the case illustrated, the diameter of 'the con tainer being l0 inchesand the electrodes being about 6 inches from the container on eitherside. A current of 250; volts at 400 amperes was permitted to flowbetween the terminals for such a length of time as was necessary toreduce the mass to a fluid containing a precipitate, the period rangingfrom 3 to '7 hours, the time depending upon surrounding conditions, thecurrent being run sufiiciently long to entirely disintegrate the mass.The current used was a 3- phase current of 250 volts on the primary, 400amperes passing throughthe reactanoe, the secondary showing about voltsat 800, amperes. This latter current was what was used with a variablereactance for control, and was varied from 800 amperes to 250 amperes,as found convenient. The current was reduced to prevent excessiveboiling, -which was the principal con trolling element, other thanoperating as fast'as the boiling would permit. Afterprecipitation, theliquid was siphoned off, and, the layers of precipitate were scraped offand the ore separated, the top layers containing probably yttriumco-mingled with variouslother lighterelements; the motherliquor alsocontained yttrium from which I obtained it by fractionalcrystallization, below which was chromium co-mingled with variouselements of about its specific gravity, or forming-imperfectprecipitation, Below that came the heavier metals, gold, platinum andother rare of introducing into a molten bath'containing iron, 7 5 0oxalates of the yttrium metals of the rare earths, bringing the entiremixture by fusion to liquefaction and while so doing protecting the saidmass with a slag formed by a slag producing substance introduced intosaid mass, then withdrawing said liquefied mixture from under said slag.

2. The process of producing an alloy containing the members of theyttrium metals of the rare earths consisting of reducing the yttriummetals of the rare earths from their oxalates, said oxalates consistingsubstantially of the relative proportion of metals of yttrium 50%,dysprosium 8%, holmium 4%, erbium 6%, thulium 1%, ytterbium 12%,lutecium 1% and terbium 8%, by introducing the same into a bath of ironhaving as a constituent carbon, then bringing the entire mass by fusionto liquefaction and while so doing protecting said mass by the slagformed by a slag producing substance introduced into said bath whereby ahard pyro-alloy of iron and the yttrium metals of the rare earths isformed, then withdrawing from under said slag said molten alloy thusproduced and formed.

3. The process of producing an alloy containing the members of theyttrium metals of the rare earths, consisting of reducing their oxalatesin the presence of carbon by heat forming a molten bath thereof,protecting said bath with a slag definitely formed for protectivepurposes, and while so protected under said slag keeping the mass in afreely molten fluid condition for an appreciable time to free the samefrom sonims, then diluting the said molten mass with another molten masscontaining iron and maintaining the joint molten masses mixed at atemperature to maintain the same freely fluid for a suflicient time tothoroughly mix while in such molten condition, then withdrawing saidmolten mixture from under said slag into a refractory lined container.

4. The process of forming an alloy of iron consisting of melting ironinto a molten bath and while in said molten condition adding carbon, andthen adding thereto oxalates of the yttrium metals of the rare earths bypouring the same on the surface of said bath, thus permitting the sameto permeate said bath to become reduced therein, whereby an alloy isformed having the property of a hard pyro-alloy.

5. The process of forming an alloy of iron consisting of forming a fusedbath of iron having a carbon content, then adding thereto oxalates ofyttrium metals of the rare earths in excess of the amount required forreduction purposes whereby the excess may combine with the iron, bypouring the same on the surface of said bath, thus permitting the sameto permeate said bath to become reduced therein whereby an alloy isformed having the property of a hard pyro-alloy.

JAMES B. GRENAGLE.

